Engine CEL Today

[CheesyMong]

Was driving down south and was behind a caravan, was doing about 100kph when I finally reached the overtaking lane dropped it into 4th and booted it...surge of powa then pop felt like a backfire or if you are in an old auto there is a jerk when it changes gear (Mines a manual by the way), but it was momentery loss of powa and then CEL light came on [S] was flashing and the cruise control light was flashing. IT wasnt me hitting the fuel cut out either and this normally doesnt cause a CEL

Anyone know what this might mean and if it sounds expensive?

Spoke to ASG as most know I have TBE 3" and Verso and he thinks it might be an Overboost protection, need to go in and verify...


Turned the car on and off CEL remained...however went for a quick trip about 5 hours later and the CEL has cleared itself...

Anyone hazard a guess what I might have done and what could have caused it?

Cheers

Joel

[Arith]

Wow, scary coincidence Joel! I was driving to work today and gave the car a kick while doing 110 on the highway. The entire car shuddered for a second, and then the CEL came on and the Cruise Control and S drive lights started flashing. I was on high boost at the time, and quickly switched to low boost for the rest of the way.

The last time the light combo came on, one of the air hoses had come loose and was causing an imbalance in the A/F ratio. Replugging the hose made the light go away after a few hours.

However this time around, a quick visual inspection revealed no loose hoses. So after work I dropped by Phat's house (I am extremely lucky to have such a great resources near by) for a quick diagnosis. Unfortunately by that time it was 7 hours after the problem started and the lights had gone away by the time I reached Phat's. He too was unable to find any loose hoses. He reckons it might have been detonation and the ECU was retarding the timing to protect itself from further damage. Might have to get look into a re-tune if this occurs again.

[swingn]

+1 for detonation.

My car sounded like it was hitting the fuel cut when flat chat in 3rd... Turns out it was detonating

[coyote]

Guys, it would be very unusual for knock to cause a check engine light. There are three parameters that get adjusted (Feedback Knock Correction, Fine Learning Knock Correction and Ignition Advance Multiplier) to correct engine knock by winding back the timing. There are also fueling corrections there.

I guess if your IAM has been reduced to .5 and you have lots of Fine Learning and Feedback Correction and it is still getting signals from the knock sensor, it would throw a code (don't know which one), but for that to happen it would have to be really, REALLY bad and not a trivial matter at all.

What I'm saying is if this is knock and not overboost, it's not just a little knock, the things must be pinging their heads off.

[CheesyMong]

Wow, scary coincidence Joel! I was driving to work today and gave the car a kick while doing 110 on the highway. The entire car shuddered for a second, and then the CEL came on and the Cruise Control and S drive lights started flashing. I was on high boost at the time, and quickly switched to low boost for the rest of the way.

The last time the light combo came on, one of the air hoses had come loose and was causing an imbalance in the A/F ratio. Replugging the hose made the light go away after a few hours.

However this time around, a quick visual inspection revealed no loose hoses. So after work I dropped by Phat's house (I am extremely lucky to have such a great resources near by) for a quick diagnosis. Unfortunately by that time it was 7 hours after the problem started and the lights had gone away by the time I reached Phat's. He too was unable to find any loose hoses. He reckons it might have been detonation and the ECU was retarding the timing to protect itself from further damage. Might have to get look into a re-tune if this occurs again.

Anyone point me in the direction of which hoses to check so I can make sure as well...i.e. where in the engine bay as I am a bit illeterate when it comes to where to find things.

ASG said he was 99% sure it was a Overboost protection.

Cheers

Joel

[coyote]

It is more likely a boost spike caused by the boost control solenoid not handling higher boost - than loose hoses.

You can turn the boost down, increase the limit or replace the solenoid. Whichever way, it's a job for ASG.

[jp928]

So if there is a Knock Sensor on the o8 gt, can anybody advise why the EcuDatascan I have fitted cant show its output? The man who makes it says it will only show data thats coming out of the port,and if there is no report of knock sensor data, it cant be shown....If there isnt a sensor, how does the ecu control advance properly? If there is, whats the signal called?
Maybe I need to hook up a laptop to the serial outlet and see whats there....?
jp08 gtb 6mt wagon

[CheesyMong]

It is more likely a boost spike caused by the boost control solenoid not handling higher boost - than loose hoses.

You can turn the boost down, increase the limit or replace the solenoid. Whichever way, it's a job for ASG.

Cool thanks for the advice Coyote

Cheers


Joel

[swingn]

+1 for detonation.

My car sounded like it was hitting the fuel cut when flat chat in 3rd... Turns out it was detonating

I might add, my engine light did not come on when I experienced this... The car just sounded like it miss fired...

[coyote]

So if there is a Knock Sensor on the o8 gt, can anybody advise why the EcuDatascan I have fitted cant show its output? The man who makes it says it will only show data thats coming out of the port,and if there is no report of knock sensor data, it cant be shown....If there isnt a sensor, how does the ecu control advance properly? If there is, whats the signal called?
Maybe I need to hook up a laptop to the serial outlet and see whats there....?
jp08 gtb 6mt wagon

It outputs a parameter called Knock Sum. That's more useful than just telling you whether or not the sensor went off, it tells you how many times it went off.

Seeing what the IAM, Feedback Correction and Fine Learning Correction are will also give you a very good idea of what is going on. Your device should be able to log those.

If IAM is 1 and the other two are all zeros, the knock sensor has not detected any detonation.

[Boxer]

I'm with coyote here - I';d seriously doubt knock to bring this situation of codes and lights.

Unless the ECU had done everything avail in its parameters to correct the situation and it was still occuring - then you might throw an error

Given the situ described - I'd say Overboost or a MAF error

[swingn]

I'm with coyote here - I';d seriously doubt knock to bring this situation of codes and lights.

Unless the ECU had done everything avail in its parameters to correct the situation and it was still occuring - then you might throw an error

Given the situ described - I'd say Overboost or a MAF error

It is possible for the engine lights to come on if you cop a bad catch of fuel.

[Boxer]

If that were the case I would surmise it is due to the circumstances I described above - ECU had corrected all avail parameters to their max values and still detected knock

Your engine will often knock under normal conditions however the extent of these knocks is quite minor and the ECU adjusts without your knowledge, the get a CEL like this means the ECU has not been able to compensate for the condition. (whether it be attributed to overboost or knock)